| Locality | Post Code |
|---|---|
| East Windsor, Mercer | 08520 |
| Ewing, Mercer | 08560, 08618, 08628, 08638 |
| Groveville, Mercer | 08620 |
| Hamilton, Mercer | 08610, 08619, 08620, 08690, 08691 |
| Hamilton Square, Mercer | 08690 |
| Hightstown, Mercer | 08520 |
| Hopewell, Mercer | 08525 |
| Lawrence, Mercer | 08648 |
| Lawrence Township, Mercer | 08648 |
| Lawrenceville, Mercer | 08648 |
| Mercerville, Mercer | 08619 |
| Pennington, Mercer | 08534 |
| Princeton, Mercer | 08540, 08542, 08544 |
| Princeton Junction, Mercer | 08550 |
| Robbinsville, Mercer | 08691 |
| Titusville, Mercer | 08560 |
| Trenton, Mercer | 08608, 08609, 08610, 08611, 08618, … |
| Upper Free, Mercer | 08691 |
| West Trenton, Mercer | 08628 |
| West Win Tow, Mercer | 08550 |
| West Windsor, Mercer | 08550 |
| Windsor, Mercer | 08561 |
| Yardville, Mercer | 08620 |